Non-equilibrium film surface assemblies from chemically distinct block copolymer micelles 

Block copolymer (BCP) self-assembly – neat, or in a homopolymer/second BCP containing molecular blend – enables complex nanostructures including spherical micelles, co-continuous cubic gyroids and Frank-Kasper phases. Emergent properties in metallic and high entropy alloys inspire a paradigm shift: treating chemically distinct BCP micelles as functional building blocks to pave a path for multicomponent assemblies with molecularly engineered property profiles. Slowing current progress are challenges associated with the structural characterization of such BCP assemblies with poor atomic contrast. Here, we demonstrate how non-equilibrium film surface self-assemblies of binary and ternary BCP micelle alloys (BMAs) can be phase inverted to generate porosity. Surface pore patterns, combined with machine-learning assisted image segmentation, allows component classification via routine scanning electron microscopy. Results are supported by mechanistic insights from Voronoi analysis, cluster analysis and Monte Carlo/Brownian Dynamics simulations, revealing rich and controllable non-equilibrium surface structural behavior. Such multicomponent materials are expected to enable emergent properties for a range of applications, including coatings for detection and sensing or phase inverted ultrafiltration membranes for affinity based separations.